1. Field
Exemplary embodiments of the present invention relate to a transistor, and more particularly, to a dual work function buried gate type transistor and a method for fabricating the same.
2. Description of the Related Art
A metal gate electrode is applied to a transistor. Gate resistance may be decreased by a metal gate electrode having a low resistance. Additionally, since the metal gate electrode has a high work function, channel dose may be decreased, leakage current may be reduced, and the performance of the transistor may be improved.
However, a problem may be caused by the high work function since gate-induced drain leakage (GIDL) increases where the metal gate electrode and impurity regions overlap, that is, the source/drain regions. Particularly, since the overlap area between a buried metal gate electrode and source/drain regions is large, it may be difficult to reduce gate-induced drain leakage (GIDL) in a buried gate type transistor.
To reduce gate-induced drain leakage (GIDL), the height of the buried metal gate electrode may be lowered. Accordingly, the overlap area between the buried metal gate electrode and the source/drain regions may be minimized.
If the height of the buried metal gate electrode is lowered, an issue is likely to be caused in that gate resistance increases and the current drivability of the transistor is degraded.
Hence, an improved trade-off characteristic between gate-induced drain leakage (GIDL) and current drivability is desirable.